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Method for a substrate with an embedded nano air-bubble porous structure

IP.com Disclosure Number: IPCOM000083111D
Publication Date: 2005-Feb-28
Document File: 5 page(s) / 124K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a substrate with an embedded nanometer (nano) air-bubble porous structure. Benefits include improved functionality, improved performance, improved design flexibility, and improved process simplicity.

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Method for a substrate with an embedded nano air-bubble porous structure

Disclosed is a method for a substrate with an embedded nanometer (nano) air-bubble porous structure. Benefits include improved functionality, improved performance, improved design flexibility, and improved process simplicity.

Background

      In conventional substrate fabrication, metal layers are typically separated by core material (CM) and insulation resin (IR). Connections are formed with via holes between metal layers. The first metal pattern is first completely covered with insulation resin. A trench is patterned into the insulation resin. A via is patterned from the trench, through insulation resin, to the first metal pattern. A metal film, such as copper, is plated in the via and trench. An IR layer with a metal via through it overlies the first metal pattern. The excess metal can be removed using an imaging process to form a patterned metal structure.

      Conventionally, as the substrate becomes thinner, line/space becomes smaller. As devices

become smaller, less expensive, and more powerful, substrate integrated circuits require more layers, smaller dimensions, and denser packaging. Consequently, the fabrication process and the  selection of materials become increasingly important. The parasitic capacitor effect caused by CM and IR results in an increasing resistance capacitance (RC) delay. To reduce the capacitor effect and improve substrate electric performance, low dielectric constant material for CM and IR must be adopted.

              Conventionally, several techniques have been used to lower the dielectric constant, including:

•             Mixing/copolymerization of low dielectric-constant compounds with conventional materials

•             Adding low dielectric-constant elements or groups to CM and IR components, such as the fluorine-doped method

•             Synthesizing of new low-dielectric constant materials for substrate CM and IR use

      However, no satisfactory results have been achieved. The synthesized materials do not meet the requirements for other material parameters, such as mechanical strength, thermal stability, and/or coefficient of thermal expansion (CTE).

      Air has the lowest dielectric constant (k) value, 0.

      Conventional nanotechnology and theory indicates nano air bubbles have no significant impact on other material properties. Nanometer-scaled materials and structure may display unique physical, chemical, and structural properties. However, the size of nano air bubbles is 1 nm to 100 nm. They are so small that the introduction of embedded nano air bubbles has no major impact on CM/IR physical and chemical properties, the substrate build-up process, and reliability.

      Conventional copolymerization and organic synthesis technologies make the formation of some nano air bubbles possible. Condensation is introduced during the polymerization of some active groups in CM or IR perform or the deco...